Rehabilitation of motor skilled impaired limbs is a desirable outcome following such impairment. For example, a stroke may be an acute clinical event, related to impairment of cerebral circulation. Acute neurologic deficits resulting from circulatory impairment can involve irreversible brain damage. The type and severity of the symptoms of such brain damage depend on a number of factors, including the location and extent of the brain tissue whose circulation has been compromised. The outcome of a stroke may vary from minimal impairment to rapid onset of coma followed by death.
Studies have shown that the incidence of stroke may be elevated by factors such as, hypertension, valvular heart disease, atrial fibrillation, hyperlipidemia, diabetes mellitus, cigarette smoking, and a familial history of stroke. Medicine is evolving efforts to try to prevent and/or minimize the risk factors associated with stroke. Unfortunately, these are preventative measures which do not address the rehabilitative needs of a stroke patient. Post-stroke rehabilitation ideally provides an environment and experience which focuses the restorative processes in the brain along the continuum of recovery.
It has been argued that bilateral movements performed in synchrony can generate neural facilitation between the cerebral hemispheres controlling the non-paretic and paretic upper-limbs. However, it not unusual for patients to have difficulty actively moving the paretic upper limb due to weakness, or other complicating factors like pasticity. Active-Passive Bilateral Therapy (APBT) relies upon a device which mechanically couples the two hands. Using APBT, stroke patients actively produce rhythmic flexion-extension of the non-paretic wrist, and mirror-symmetric movements of the paretic hand are generated through a mechanical linkage that confers an inertial advantage. During active-passive bilateral wrist flexion-extension movements, there is a measurable reduction in inhibition within the motor cortex of the passive (stroke affected) hemisphere. This reduction in inhibition is thought to arise from synchronous somatosensory feedback generated in both hemispheres by use of the device, such that the upper limbs become “functionally coupled”. “Disinhibition” is a neurophysiological context which has been shown to facilitate plastic reorganisation (or re-wiring of cells) within the motor cortex. There is mounting neurophysiological evidence that APBT promotes disinhibition and re-balancing of motor cortex function in chronic stroke patients who also showed improved of upper limb function after a period of self-administered therapy preceded by APBT.
The use of any system which encourages re-training of brain functionality to in turn promote increased physical control of such an impaired limb is desirable. Where the patient of a stroke has a resultant physical impairment, such as reduced motor capabilities of a limb (for example, arm, wrist, foot, fingers or leg movement etc), re-training of brain functionality for limb control may be assisted by repetitive movements.
In a paper entitled ‘Rhythmic Bilateral Movement Training Modulates Corticomotor Excitability and Enhances Upper Limb Motricity Poststroke: A Pilot Study’ (J Clin Neurophysiol 2004; 21: 124-131), it is hypothesised that simultaneous activation of homologous muscles may promote the recovery of the function of an affected limb following a stroke. For example, bi-manual rehabilitation of opposing limbs appears to hold merit with rehabilitation efforts, for example in the re-training of brain function. Attention has been focused on systems of physical exercises which are based on small and/or repeated movement. Further, allowing a stroke patient to practice, repeatedly, the necessary movements required of a limb following impairment of such a limb may encourage the treatment of physical reconditioning and mental redevelopment. This may enable the patient to at least gain some, or an increased level of control over the impaired limb.
A device which can assist with creating or providing the above beneficial repetitive movement would be advantageous.
Therefore, one object of the present invention may be to provide a device which allows stroke patients to move their limbs, such as their hands, in way which causes changes in the balance of inhibition and excitation in the brain, allowing it to respond better to use of the affected hand after using such a device.
A further object of the present invention may be to provide a training or rehabilitative device which will go at least some way towards addressing the foregoing problems or which will at least provide the industry with a useful choice.
In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.